The purpose of this project is to study the effects of various chemicals on drug and xenobiotic metabolism in various types of cells in the lung. Of particular interest are those compounds which are metabolized by the cytochrome P-450 monooxygenases. Both rats and rabbits are being used as experimental animals. The rat was chosen because it, like man, is subject to induction of these metabolizing systems by certain drugs and chemicals. The rabbit is being used as a model because of the particularly high xenobiotic metabolism in the lungs of this species. Currently, different cell types, especially alveolar type II cells and Clara cells are being isolated so that a detailed examination of the toxication-detoxication processes in purified cell types and in individual cells may be carried out. Different intrinsic abilitities to metabolize various chemical compounds including benzo(a)pyrene, and these activities are inducible in rats to different extents. Also, treatment of rats with monooxygenase inducers alters the balance of toxication-detoxication enzyme systems in the different lung cell types. The development of microspectrofluorometric techniques for the measurement of xenobiotic metabolism has enabled measurements to be made on single isolated cells, rather than on pooled fractions of cells.